MAKER: CHARLES BAKER COMPANY

MODEL: 'Nelson No. 2'

c. 1899 (1898-1907)

SIGNED:'C. BAKER, 244, HIGH HOLBORN, LONDON'

SERIAL NUMBER: none

DESCRIPTION:

This large microscope arises from a tripod base. It is five and one half inches from the level of the feet to the middle of the inclination joint. The splay of the front legs is seven inches (outside edge to outside edge). The front feet have slots to allow the microscope to be secured to a surface, a feature most useful for photography. Some of the earlier models of this stand, did not have the slots. In addition, all three feet are held in place by screws from the bottom and can be removed to allow the entire stand to be anchored from below by screws coming up from a base. The microscope can incline from
vertical to horizontal and be held at the desired angle by tightening the large lever on the right side. The substage carries its condenser in a centerable mount and focuses by diagonal rack and pinion on the left side of the microscope, though most if not all engravings show it on the right side. An unusual feature of the substage is the provision of three positions for the condenser carrier to allow different types and lengths of substage apparatus; only some examples of this model had this option, a provision also found on some Grand Van Heurck models made by Watson. There is no substage fine adjustment on this example, and this provision became optional in 1895. The main optical tube coarse focus is by diagonal rack and pinion, fine is by 'Campbell' differential screw controlled from the underside of the arm. The fine focus control is calibrated, and has a groove for allowing its control by a cord and pulley system during photography. The gimballed mirror is plano-concave and on a swinging arm which is in turn, attached to a sleeve which can run up or down the fixed
tailpiece. The mechanical stage, a variation on the Mayall stage of 1885, has separate controls for the X and Y direction, and bright nickel vernier scales for each. It was the standard stage for the Nelson No 2 microscope. It differs from the true Mayall version, (which was indeed an option for the Nelson microscopes)*. On the Nelson No 2 on this web page, the entire stage rotates manually, but there are no scales for the rotational movement and no provision for centering the stage. There is a triple nosepiece objective changer. The outer draw-tube has rack and pinion adjustment with the knob on the left side; examples exist with this adjustment on the other side as well. There is an additional inner drawtube, the same kind of arrangement as Watson's Van Heurk and Royal models. The drawtubes are both calibrated.
The original case is present, though the top handle is a modern replacement. Lock and key are intact. There are five oculars, three of which are the later standard diameter of 22 mm, and they make use of an adapter; the other two are the older type of 'top-hat' design. There are also five objectives. Two of these are by Bausch & Lomb, one by Zeiss and two by Swift. This is not unusual, as Baker often supplied objectives made by others, especially Zeiss.

*The true Mayall stage has no plates to move the slide in either direction, rather the slide is pushed around the top of the stage in all directions by concentric controls activating the slide holder which grasps the slide from its sides.